An antiemetic drug is something that is given to help a patient with nausea and vomiting. There are many drugs in this category because there are many reasons a patient might be nauseated, from chemotherapy to motion sickness, and it takes a different drug to give a patient relief from different causative factors. The most popular antiemetic drugs that are given in hospitals are ondansetron, metoclopramide, promethazine and prochlorperazine. These are just a rough guide, however, and the actual drugs used can vary according to the regulations of the hospital. The world of antiemetic drugs is actually a much broader category.
Ondansetron probably is the most popular of the antiemetic drugs, and it is part of the serotonin receptor blockers. This drug blocks the receptors for serotonin in the gut and helps relieve some of the nausea and vomiting that come after surgery or things such as food poisoning. Another serotonin receptor blocker is mirtazapin.
Dopamine antagonists are antiemetic drugs that are great for chemotherapy because they act directly on the receptor sites in the brain. They bypass all of the workings of the gastrointestinal tract and are, thus, more effective. Prochlorperazine is part of this category and was the drug of choice for a very long time before ondansetron. Metoclopramide also is in this category, but it has the added effect of increasing intestinal motility. This makes the stomach empty faster and cuts down on mechanical sources of nausea and vomiting.
Antihistamines such as diphenhydramine and dimenhydrinate are available over the counter and have antiemetic effects to them. There is some evidence that they are good for morning sickness and motion sickness. These are readily available, so they might be worthwhile for patients to try in such cases as chemotherapy and for the side effects of opioid analgesics. They might be just as effective as the stronger medications. Promethazine also is in this category, although it is stronger and is usually through an intravenous line in the hospital.
Cannabinoids such medical marijuana are one of the most controversial antiemetic drugs. It would be difficult to get this sort of treatment in most hospitals. There is evidence, however, showing that cannabis does have strong antiemetic effects for those who are undergoing chemotherapy.
The field of antiemetic drugs has led to much research because so many people suffer from nausea and vomiting as a side effect of chemotherapy or from opioid analgesics. The anticholinergic scopolamine has been made into a transdermal patch that is often used by people going to surgery, going on airplanes or getting chemotherapy. Herbs such as ginger and peppermint have been studied as possible alternatives to medical drugs for antiemetic relief. Indeed, there are many options available when it comes to antiemetic drugs.